I bought a 50 lb bag from a local commerical pool supply company for about a buck a pound. They also have 50 lb bags of hypo and sodium carbonate. Also look for places that service big boilers for heating old commerical buildings, they use it as an oxygen scavenger in the boilers. I saw the kodak stuff going for about $10.00/lb at the local photoshop.
That is a great tip. I am guessing the hypo is the sodium hypo thiosulfate.
The hypo bags say "sodium thiosulfate, prismatic rice, photo grade". It works just fine. I find I can fit just about a whole bag in a 5 gallon bucket, and use a screw on lid with a gasket, got it at the local big box hardware store.
Look for places that are right on the railroad tracks, they buy by the boxcar load. The sales people are usually clueless, but there should be a guy in the back who knows everything, you must speak to him.
So I did and here is a brief summary of the experiment and some results...
Originally Posted by Photo Engineer
I mixed up two developers. Developer A is: 10g Metol, 100g Sulfite, 8g Borax and water to make 1 liter. Developer B is the same as developer A except that B has only 25g sulfite per liter.
I shot six sheets of fresh Illford FP4+ rated at box speed. Both sheets on either side of a film holder were exposed exactly the same and, of course, were of the same scene at nearly the same time and same light. Two scenes have what I consider to be flat light and the third scene is contrasty afternoon sunlight.
One sheet from each film holder was developed in Dev. A and the other sheet in dev. B. In both cases, the dev time was 8 minutes with continuous rotational agitation. I used a Jobo Expert drum on a unicolor roller base with the direction reversing switch bypassed (so, it never changes direction).
Examining the negatives it is immediately apparent that dev. A built up more negative density and that dev. B wasn't able to hold the shadow detail.
Some scans follow - these are unadulterated negative scans - please forgive the crudity of the presentation - I simply scan, rotate, remove the color and save. Nothing more.
Dev A is on the left.
These were done with a crown graphic and 150mm Xenar in flat lighting.
Last edited by BradS; 03-15-2008 at 01:44 AM. Click to view previous post history.
dev A is again on the left.
Modern, multicoated and super contrasty 1355 Nikkor-W in harsh light.
Last edited by BradS; 03-15-2008 at 01:45 AM. Click to view previous post history.
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I should also mention that I added the Borax in hopes that it would make both developers solutions have roughly the same pH. What I found was that dev A has a pH of about 8.3 and dev B has a pH of about 7.7 after developing three sheets of 4x5 each. I suppose this explains a lot of why the shadows didn't hold up as well in the reduced sulfite dev.
First of all borax will lower the ph of any sulfite activated
Originally Posted by BradS
developer. The less the sulfite the more profound the
lowering. Sulfite alone activated developers have
about as low a ph as any need to go.
Second your method of agitation does not make allowance
for bromide's drag on development or for local depletion.
Metol is sensitive to bromide and your results have me
thinking that it must not be used in just any manor.
For myself I've gotten very good shadow results
and intend to continue with my 8-80 formula at
a 1:7 dilution. At that dilution D-23 is a semi-
compensating developer. Your supply of
sulfite will last and last. Dan
Since the formulas are the same except for sulfite and pH, there are two comments I would have. First, the pH difference has obscured the results and second the question remaining is ''what would happen if the prints were made opitmally for the development of the film?"
Of course, there is also the question of what zero sulfite would have done.
But, basically you see the change. Kodak films are released by testing in D76. (At least they were when I was there.) Changes from this 'center point' of developer formulation will change the results rather strongly. This is true of all B&W and Color films and papers.
Also, I'm sure the results would have been different if the pH's had been made the same to start by increasing the amount of borax in the developer with less sulfite.
...or just bump the speed down to 64.